An ab initio based full-dimensional global potential energy surface for FH2O(X2A′)and dynamics for the F + H2O → HF plus HO reaction

A global potential energy surface (PES) for the ground electronic state of FH2O is constructed based on more than 30 000 ab initio points at the multi-reference configuration interaction level. The PES features a pre-reaction van der Waals well and two post-reaction hydrogen-bonded complexes, as well as a reactant-like transition state with a classical barrier of 3.8 kcal/mol. The adiabatic F + H2O -> HF + OH reaction dynamics on this PES was investigated using a standard quasi-classical trajectory method. In agreement with experiment, the HF product contains significant vibrational excitation with limited rotational excitation, while the OH product is internally cold, reflecting its spectator role in the reaction. The products are primarily scattered in the backward direction, consistent with a direct abstraction mechanism. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748857]